body,html{
	width: 100%;
	height: 50%;
}
.main{
	width: 100%;
	height: 100%;
	position: relative;
	display: flex;
}
.center{
	display: flex;
	flex-wrap: wrap;
	width: 100%;
}
.item{
	display: flex;
	margin: 4px;
	align-items: center;
	justify-content: center;
}